Messages in this thread | | | Date | Wed, 14 Apr 2010 17:30:39 -0700 | Subject | Re: Dmaengine query | From | Dan Williams <> |
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On Tue, Apr 13, 2010 at 11:26 PM, rd bairva <rbairva@gmail.com> wrote: > Hi Dan, > > I am currently writing dmaengine compatible DMA driver for our ARM > based architecture, But I am facing some performance issues doing > that. > > 1. dmaengine says callback should run in tasklet, and next transfer > cannot be scheduled from the callback. > > Due to these restrictions I am getting some performance issue while > playing sound in our architecture. > > > Can callback call in DMA driver be placed out of spin_lock to submit > new operations from callback? (only in asynchronous case) > > is this Ok? please comment.
Other dma driver authors are dropping the lock across the call to the callback in the mem-to-io case. The compliance points in the documentation are primarily targeted at the expectations of the async_tx api. In the mem-to-io (slave dma) model you are not using the async_tx api.
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